High-field metamagnetism in the antiferromagnet CeRh2Si2

Magnetic field-induced quantum criticality, as well as that induced by pressure, is an important issue in condensed-matter physics. High magnetic fields permit to tune antiferromagnets to a polarized paramagnetic regime through a quantum phase transition. We have performed a series of measurements (torque, magnetostriction, thermal expansion and resistivity, up to 50 T) determining the high-field magnetic phase diagram of the antiferromagnet CeRh2Si2. The magnetic field temperature phase diagram is found to be composed of (at least) three different antiferromagnetic phases. At magnetic fields above 26 T, the system is polarized paramagnetically. An analysis of the resistivity data at low temperature shows an enhanced effective mass of the quasiparticules over a broad range around the magnetic field-induced quantum instability. A comparison is made between pressure- and field-tuned criticalities in CeRh2Si2, but also in the well-documented case of CeRu2Si2. It points out that both kinds of criticality lead to similar effective mass enhancements, which suggests that they are governed by common features.